Reinstallable GHC

This patch allows ghc and its dependencies to be built using a normal
invocation of cabal-install. Each componenent which relied on generated
files or additional configuration now has a Setup.hs file.

There are also various fixes to the cabal files to satisfy
cabal-install.

There is a new hadrian command which will build a stage2 compiler and
then a stage3 compiler by using cabal.

```
./hadrian/build build-cabal
```

There is also a new CI job which tests running this command.

For the 9.4 release we will upload all the dependent executables to
hackage and then end users will be free to build GHC and GHC executables
via cabal.

There are still some unresolved questions about how to ensure soundness
when loading plugins into a reinstalled GHC (#20742) which will be
tighted up in due course.

Fixes #19896

8 files changed, 14 insertions, 8 deletions

diff --git a/utils/genprimopcode/genprimopcode.cabal b/utils/genprimopcode/genprimopcode.cabal
index d6dc8b58ec..2dc581dc49 100644
--- a/utils/genprimopcode/genprimopcode.cabal
+++ b/utils/genprimopcode/genprimopcode.cabal
@@ -15,7 +15,7 @@ Description:
     * an LaTeX document describing the primitive operations.
 Category: Development
 build-type: Simple
-cabal-version: >=1.10
+cabal-version: 2.0
 
 Executable genprimopcode
     Default-Language: Haskell2010
@@ -26,3 +26,4 @@ Executable genprimopcode
                    Syntax
     Build-Depends: base       >= 4   && < 5,
                    array
+    build-tool-depends: alex:alex >= 3.2.6, happy:happy >= 1.20.0
diff --git a/utils/hp2ps/hp2ps.cabal b/utils/hp2ps/hp2ps.cabal
index 1b48694564..482ea772b9 100644
--- a/utils/hp2ps/hp2ps.cabal
+++ b/utils/hp2ps/hp2ps.cabal
@@ -9,13 +9,16 @@ Synopsis: Heap Profile to PostScript converter
 Description: XXX
 Category: Development
 build-type: Simple
+extra-source-files: AreaBelow.h AuxFile.h Axes.h Curves.h Defines.h Deviation.h
+                    Dimensions.h Error.h HpFile.h Key.h Main.h Marks.h PsFile.h Reorder.h Scale.h
+                    Shade.h TopTwenty.h TraceElement.h Utilities.h
 
 Executable hp2ps
     Default-Language: Haskell2010
     Main-Is: Main.c
     extra-libraries: m
     C-Sources:
-       AreaBelow.c Curves.c Error.c Main.c
+       AreaBelow.c Curves.c Error.c
        Reorder.c TopTwenty.c AuxFile.c Deviation.c
        HpFile.c Marks.c Scale.c TraceElement.c
        Axes.c Dimensions.c Key.c PsFile.c Shade.c
diff --git a/utils/hpc/hpc-bin.cabal b/utils/hpc/hpc-bin.cabal
index 28cc2af49b..6e344de856 100644
--- a/utils/hpc/hpc-bin.cabal
+++ b/utils/hpc/hpc-bin.cabal
@@ -10,7 +10,7 @@ Synopsis: XXX
 Description: XXX
 Category: Development
 build-type: Simple
-cabal-version: >=1.10
+cabal-version: 2.0
 
 Executable hpc
     Default-Language: Haskell2010
@@ -27,6 +27,8 @@ Executable hpc
                    HpcUtils
                    Paths_hpc_bin
 
+    autogen-modules: Paths_hpc_bin
+
     Build-Depends: base       >= 4   && < 5,
                    directory  >= 1   && < 1.4,
                    filepath   >= 1   && < 1.5,
@@ -34,3 +36,4 @@ Executable hpc
                    array      >= 0.1 && < 0.6,
                    hpc        >= 0.6.1 && < 0.7
 
+    build-tool-depends: happy:happy >= 1.20.0
diff --git a/utils/runghc/Main.hs b/utils/runghc/Main.hs
index 9ed650410d..5e447ed99f 100644
--- a/utils/runghc/Main.hs
+++ b/utils/runghc/Main.hs
@@ -110,7 +110,7 @@ parseRunGhcFlags = f mempty
 
 printVersion :: IO ()
 printVersion = do
-    putStrLn ("runghc " ++ VERSION)
+    putStrLn ("runghc " ++ CURRENT_PACKAGE_VERSION )
 
 printUsage :: IO ()
 printUsage = do
diff --git a/utils/runghc/ghc.mk b/utils/runghc/ghc.mk
index 65a3ca88d6..76272d9d80 100644
--- a/utils/runghc/ghc.mk
+++ b/utils/runghc/ghc.mk
@@ -17,7 +17,6 @@ utils/runghc_dist-install_SHELL_WRAPPER = YES
 utils/runghc_dist-install_INSTALL = YES
 utils/runghc_dist-install_INSTALL_INPLACE = YES
 utils/runghc_dist-install_INSTALL_SHELL_WRAPPER_NAME = runghc-$(ProjectVersion)
-utils/runghc_dist-install_EXTRA_HC_OPTS = -cpp -DVERSION="\"$(ProjectVersion)\""
 
 # Be explicit about which version of ghc to call (#9054).
 define utils/runghc_dist-install_INPLACE_SHELL_WRAPPER_EXTRA
diff --git a/utils/runghc/runghc.cabal.in b/utils/runghc/runghc.cabal.in
index ffe75756f7..3afeb425ee 100644
--- a/utils/runghc/runghc.cabal.in
+++ b/utils/runghc/runghc.cabal.in
@@ -32,4 +32,4 @@ Executable runghc
                    filepath
 
     if !os(windows)
-      build-depends: unix
\ No newline at end of file
+      build-depends: unix
diff --git a/utils/touchy/touchy.cabal b/utils/touchy/touchy.cabal
index 21a774b1fa..5c28c664fc 100644
--- a/utils/touchy/touchy.cabal
+++ b/utils/touchy/touchy.cabal
@@ -13,4 +13,3 @@ build-type: Simple
 Executable touchy
     Default-Language: Haskell2010
     Main-Is: touchy.c
-    C-Sources: touchy.c
diff --git a/utils/unlit/unlit.cabal b/utils/unlit/unlit.cabal
index e49fd8558b..0707d5d95a 100644
--- a/utils/unlit/unlit.cabal
+++ b/utils/unlit/unlit.cabal
@@ -9,9 +9,10 @@ Synopsis: Literate program filter
 Description: XXX
 Category: Development
 build-type: Simple
+extra-source-files: fs.h
 
 Executable unlit
     Default-Language: Haskell2010
     Main-Is: unlit.c
-    C-Sources: unlit.c, fs.c
+    C-Sources: fs.c
     Includes: fs.h